I need to deal with work

Telling your employer about your prescription

Whether to tell, what your employer can and cannot do about drug testing, and where your condition gives you rights at work.

The short answer

There is no single rule. Start with your contract and your workplace's drug and alcohol policy, which may require you to declare medicine that could affect your work. A workplace drug test cannot tell prescribed cannabis from illegal cannabis, so it usually helps to tell occupational health or HR before any test. If your condition counts as a disability under the Equality Act 2010, your employer must make reasonable adjustments.

Do it here

Should I tell my employer?

Three questions about your job. What comes back is from the guide below, not advice on your own situation.

Does your contract or drug and alcohol policy ask you to declare medicine that could affect your work?
Is your work safety-critical, such as driving, operating machinery or working at height?
Does your workplace test for drugs?

Write the note to HR or occupational health

You send it yourself. Nothing you type is sent to or kept by this site.

Subject: A confidential conversation about a prescribed medicine

Hello,

I would like to speak to you in confidence about a medicine I have been prescribed.

It is a cannabis-based medicine, prescribed for me by a specialist doctor. I can give you a copy of my prescription or a letter from my clinic that names the medicine and confirms it is prescribed.

I would like to explain how it is taken and what my prescriber has said about work and driving, and to talk about any adjustments that would help.

Please could what we agree be put in writing.

Thank you,
[your name]
Open in my email

Check your contract and policy first

Many employers have a drug and alcohol policy, and some require staff to declare any medicine that could affect their work. This is most common where safety is involved, such as driving, operating machinery or working at height. Read the policy before you decide what to say, because it tells you who to tell and what is expected.

Drug testing at work

The government's guidance on testing says:

  • "Employers have to have consent if they want to test for drugs." Usually this is through a health and safety policy in the contract or staff handbook.
  • Employers should limit testing to employees who need to be tested, make sure tests are random, and not single out particular employees unless the nature of their job justifies it.
  • "Workers cannot be made to take a drugs test but if they refuse when the employer has good grounds for testing, they may face disciplinary action."

If your workplace tests, a prescribed product containing THC can produce a positive result. Telling occupational health or HR beforehand, with a copy of your prescription or a letter from your clinic, means a positive result has an explanation on record before it happens.

Your condition and the Equality Act

You are disabled under the Equality Act 2010 "if you have a physical or mental impairment that has a 'substantial' and 'long-term' negative effect on your ability to do normal daily activities." Substantial means more than minor or trivial. Long-term means 12 months or more.

Where that applies, "employers must make reasonable adjustments to make sure workers with disabilities, or physical or mental health conditions, are not substantially disadvantaged when doing their jobs."

These rights attach to your condition. The sources below do not say that an employer must allow a particular medicine to be taken at work, and they do not override safety rules. What is reasonable depends on your job, so ask for a conversation about adjustments, for example your duties or hours while a new medicine settles.

Being fit for work

Whatever your employer knows, do not do safety-critical work if your medicine has left you drowsy or less alert. Ask your prescriber what to expect and whether timing your doses around work would help.

How to raise it

  • Ask to speak to occupational health, or to HR, in confidence.
  • Bring a copy of your prescription or a clinic letter that names the medicine and confirms it is prescribed.
  • Explain how it is taken and what your prescriber has said about work and driving.
  • Ask for what is agreed to be put in writing.

Where to get advice

For advice on your own situation, contact Acas, Citizens Advice or your trade union. This guide is general information, not legal advice.

Sources

Checked on 5 October 2026. Laws and official guidance change, so read the source before you rely on anything here.

This guide has not yet been reviewed by a qualified professional. It summarises the official sources listed above. Read those, or take advice, before you rely on it.